Problem: Gabriela has dinner at a cafe and the cost of her meal is $\$45.00$. She would like to leave a $15\%$ tip. What is her total bill including tip?
Explanation: The tip amount is equal to $15\% \times \$45.00$ We can find the tip by first calculating a $10\%$ tip and a $5\%$ tip, and then adding those two numbers together. To calculate a $10\%$ tip, move the decimal point in $\$45.00$ one place to the left. $10\%$ $\times \$45.00$ $\$4.50$ To calculate a $5\%$ tip, divide the $10\%$ tip amount in half. $5\%$ $\times \$45.00 = $ $\$4.50$ $ \div 2 = $ $\$2.25$ Adding the two amounts together gives us $\$4.50$ $\$2.25 =$ $ \$6.75$ The cost of the meal plus the amount of the tip will equal the total bill amount. $\$45.00 + \$6.75 = $ $\$51.75$ The total cost of the bill is $\$51.75$.